Currently in order to broadcast by relay from a broadcast spot (broadcast scene) or the like, video/audio data that is shot/collected at the broadcast spot is radio-transmitted using SNG (Satellite News Gathering) using a communication satellite or using a FPU (Field Pickup Unit) enabling relay transmission via microwaves, thus transmitting video materials/audio materials for broadcasting to a broadcasting station. In general, in the relay using a communication satellite or a FPU, a mobile relay station called an outside broadcasting van is placed at a broadcast spot, and a line between the mobile relay station and an antenna on the broadcasting station side or at a base station is a dedicated line through which video materials/audio materials for broadcasting only are transmitted.
Conventionally, as shown in FIG. 15, for example, relay can be performed using a communication satellite or a FPU, and an outside broadcasting van 3200 equipped with switcher facility is placed at a broadcast spot, and thereby videos shot by a plurality of cameras 3100 are selectively transmitted from the outside broadcasting van 3200, thus transmitting the videos to a broadcasting station.
The following Patent Document 1, for example, discloses a technique for a more stable main link to transmit a data packet from a video output device (video source) to a display device (video display). According to this technique, a training session via an auxiliary channel is provided and prior to transmission of a data packet via the main link, a training signal is transmitted via the auxiliary channel.
The following Patent Document 2, for example, discloses a technique, in a system configured to transmit videos from a plurality of cameras to an image display device via a communication line, of making the image display device designate a camera from which video is to be received in accordance with selection schedule information.